1. Field of the Invention
The present invention is concerned with an apparatus and method for continuous handling and processing of one or more elongated, printed webs in order to eliminate sequential processing, rewind, storage, unwinding and subsequent processing of individual webs as has heretofore been the practice in production of multiple-page printed items. More particularly, it is concerned with an improved apparatus and method of the type described in U.S. Pat. No. 4,307,830 entitled "Web Fed Printing Collator Processing Unit and Method." This patent is hereby incorporated by reference herein.
2. Description of the Prior Art
The production of multiple-page printed items such as business forms, booklets or small catalogs has traditionally been accomplished by performing a number of essentially discrete steps. That is to say, it is the common practice to separately print elongated webs which are temporarily wound and stored in large rolls. Other common practices include production of sheets, signatures, or zig-zag folded webs. These are also temporarily stored in the form of individual stacks. After all of the material has been printed, the rolls or stacks of paper are moved to a bindery site which conventionally includes final processing equipment such as a web fed roll collator, gatherer, bindery or other known equipment. During the final processing operations, the individual webs, sheets, signatures, etc. are collated, placed in registration and the complete set subjected to final processing. The latter may involve, e.g., cross-perforation and Z-folding, gluing and cutting, staple bindery, and/or further folding and trimming.
A persistent problem in connection with these operations stems from the fact that they are relatively labor intensive, i.e., the non-continuous nature of the process inherently creates a situation where a number of workers must be employed for handling and to carry out the many startup operations. Therefore, the time and expense required for production of multiple-page printed items is correspondingly significant.
The above factors are of particular importance in connection with so-called "short runs." In such cases labor costs represent a large proportion of the total expense in producing the finished product. In fact, in many cases the cost of producing a small number of the finished product is very close to the cost for producing a much larger number. Further, short runs often represent a significant part of a printer's business, and therefore any means of reducing costs in this area represents a real advancement in the art.
Another problem inherent in current equipment is the recognition and handling of waste product. Because the material is typically being handled in the form of tightly wound rolls or tightly packed piles of sheeted or folded material, it is difficult to recognize material which is damaged or incomplete. In many cases, this waste product is not found until final processing is being completed; in other cases, the final product is shipped with waste material included. An important related problem is that often the extent of waste material within a roll or pile is unknown. It is therefore difficult to "make things come out even." For example, when all of the acceptable material from shortest "good" roll has been used, there may remain a substantial amount on the other rolls which is then typically dumped into waste bins. The same is true with respect to runs involving collation or gathering of sheets or signatures from storage stacks. During printing from roll to roll, the pressman will insert a "flag" to indicate bad material. Each printed roll may have several flags. Thus, during collation, it is necessary to stop the collator at each flag and discard the waste product. Thus it is common practice for the press operator to print an excess length of web after an error has occurred to compensate for the unknown length of unsuitable material. The result is considerable wastage.
When printing from roll to sheet or sheet to sheet, unless the operator perceives that bad material is being printed and makes an accurate determination of how much he removes, before again directing the sheet to the accumulated stack, waste can again occur from overprinting to make up for an unknown loss, or the erroneously printed material may simply be buried in the storage stacks and present an unknown problem to the bindery operation which is not discovered until encountered during gathering or collating. Thus the problem is not only a factor of unknown wastage in printing, but inability to observe the printed material in stacked form until it is actually directed into the bindery machines.
Another problem present in currently used equipment concerns the drying of inks. All normally used inks require a certain amount of time to reach a dry condition when they will not smear or smudge; this time typically varies from a few seconds to several hours. Some of the current methods used to deal with this problem involve high energy dryers which attempt to speed up the drying process, typically to fractions of a second. Other methods include physical separation of the product, using such things as granular dusting powder. With materials stored in piles, intermediate supports or bars often have to be inserted into the pile to prevent excessive weight being transferred to the lower sheets where "offsetting" would occur.
Still another problem in current equipment is that most machines are essentially single purpose. For example, the several pieces of equipment necessary to produce business forms cannot be used to make booklets, or small newspapers or magazines. The expenditures necessary to obtain equipment to produce several types of products is quite prohibitive, particularly for short run production.
A recent, significant breakthrough in the art designed to overcome the problems noted above is described in the above referenced U.S. Pat. No. 4,307,830. This patent discloses an apparatus and method wherein a plurality of spaced web-supporting elements such as individual, trackmounted, shiftable bars are employed with web feeding and alignment means for feeding webs onto the elements in a draped relationship for support thereby. In this manner storage-in-process of the printed webs is provided, with the consequent elimination of many of the labor intensive steps associated with production of multiple-page printed items.